The invention relates to a valve and to a male valve member for cooperation with a female member to form a fluid T coupling.
Valves for forming fluid T couplings are used in a variety of different applications. One of the most important of those applications is in surgical aspirators which are used to remove fluid from a body during surgery. Typically, the valve is formed of a male and female member with the female member being mounted on a housing which similarly mounts a pump and includes the various necessary control and electronic elements. Such valves and associated equipment are described in greater detail in U.S. Pat. No. 4,418,944.
In this arrangement, the female member has a generally cylindrical receptacle with a fluid flow opening into the receptacle for providing pressure relief to the T coupling upon command. The male member and attached inlet and outlet tubing are preferably supplied as a sterile unit and can be either disposable or reusable After each operation, the male member and tubing are removed, discarded, and replaced with a fresh sterile unit. Each such male member is formed with a first bore extending between the inlet and outlet tubes and a second bore communicating the first bore to the fluid flow opening of the female member to provide pressure relief. Normally the fluid flowing is air although some liquid may be entrained if present. A one-way valve is normally provided either in the female member or within the housing for preventing fluid flow through the second bore and into the housing and limiting flow through the second bore to pressure relief.
Some moisture, however, inevitably finds its way into the fluid flow opening of the non-disposable female member and the passageway between the one-way valve and that fluid flow opening Since the fluid is removed from the body during a surgical procedure, it is rich in bacteria and the moist passageway provides an ideal medium for growth thereof. Although the distance between the passageway in the housing and the patient can be several feet, bacterial migration to the patient can take place, particularly if a sterile male member has been installed a considerable time before the operation takes place.
According to one aspect of the present invention, a one-way valve is provided in the male valve member so that fluid cannot reach the fluid flow opening of the female member. The valve member can be easily used on existing units as described above. The existence of a second one-way valve has no adverse effect on operation and simply provides complete protection against bacterial contamination.
One particularly attractive and satisfactory way of providing such valve is to utilize a sleeve which preferably tapers and covers the opening of the second bore into the first bore. The sleeve, in fact, may simply be the end of the inlet tube which connects to the hand-held surgical aspirating device. When the pressure in the second bore exceeds the pressure in the first bore, due to a command for pressure relief, the sleeve is pushed aside by the air flow and the T coupling functions normally. However, when the pressure in the first bore exceeds the pressure in the second bore, the sleeve prevents any flow of fluid or gas into the second bore which could contaminate the fluid opening of the female member and the associated passage as noted above.
The male valve member described in the above patent is formed of a rigid base portion and a separate attached relatively resilient face portion. The cross-section of the male member in a plane transverse to the first bore extending therethrough is asymmetrical. The male member is installed by simply placing it in the cylindrical receptacle and rotating by finger pressure on an outwardly extending lever until the second bore, which extends through the resilient member, engages the fluid flow opening. The asymmetrical cross-section of the male member results in a locking of the male and female together in the proper position after rotation.
While generally satisfactory, the above-described male member has a number of drawbacks, in addition to the possible contamination problem discussed above. First, the member is formed in two separate parts which must be attached together leading to additional complexity in assembly and additional cost. The required asymmetrical configuration of the male member leads to additional expense. Although camming surfaces provide a "feel" when the male member has been rotated to its desired position, it is possible that full engagement may not take place unless the person installing the male member takes care to make sure that it is rotated to the full desired extent.
According to a further aspect of the present invention, the disposable male valve member is inserted and locked into place, not by rotation, but either by sliding movement along the direction in which the first bore extends or by simply pushing the male member in a linear direction until it properly engages with the female receptacle. In both instances, this is accomplished by providing at least part of the male member with resilient portions which are compressed when the male member is inserted and which provide a positive lock of the male and female members together with the second bore communicating with the fluid flow opening. Preferably, the entire valve member is formed of a resilient material, such as silane plastic, which can be easily formed as a unitary member, eliminating the need for any assembly and reducing expense of the device.
At least a portion, however, of the valve member which is inserted into the cylindrical receptacle is of resilient material and normally has dimensions greater than the dimensions of corresponding portions of the receptacle which contact the male portion when the male and female portions are in cooperation. Compression of the male portions upon insertion positively locks together the male and female members with the second bore communicating with the fluid flow opening.
In a first embodiment of the invention, the valve member includes a generally cylindrical portion adapted for insertion into the cylindrical receptacle. A plurality of resilient protrusions are provided adjacent each end and extending more than one-half around the circumference of this partially cylindrical part. These resilient portions contact and firmly lock together the male and female members as described above. In addition, a stop member is provided extending upwardly from the generally cylindrical portion for contacting the corresponding surface of the female member when the male member is properly in position with the second bore sealingly engaged with the fluid flow opening.
According to a second embodiment of the present invention, the male member is made entirely of resilient material and is tapered in the direction along which the first bore extends from a stop surface. The male member is simply inserted into the cylindrical receptacle of the female member and slid along the cylindrical receptacle in the direction in which the bore extends. The tapered material is thus compressed to lock together the male and female members with the stop surface contacting an associate stop surface of the female member when the second bore is sealingly engaged with the fluid flow opening.
Other objects and purposes of the invention will become clear from the following detailed description of the drawings.